module ggplotd.aes;

import std.range : front, popFront, empty;

version (unittest)
{
    import dunit.toolkit;
}

import std.typecons : Tuple;

// TODO Also update default grouping if appropiate

///
static auto DefaultValues = Tuple!( 
    string, "label", string, "colour", double, "size",
    double, "angle", double, "alpha", bool, "mask", double, "fill" )
    ("", "black", 1.0, 0, 1, true, 0.0);

/++
    Aes is used to store and access data for plotting

    Aes is an InputRange, with named Tuples as elements. The names
    refer to certain fields, such as x, y, colour etc. If certain fields
    are not provided then it provides a default value (see DefaultValues).

    The fields commonly used are data fields, such as "x" and "y". Which data
    fields are required depends on the geom* function. By default the named 
    Tuple holds the fields:
    $(UL
        $(LI "label": Text labels (string))
        $(LI "colour": Identifier for the colour. In general data points with different colour ids get different colours. This can be almost any type. You can also specify the colour by name or cairo.Color type if you want to specify an exact colour (any type that isNumeric, cairo.Color.RGB(A), or can be converted to string))
        $(LI "size": Gives the relative size of points/lineWidth etc.
        $(LI "angle": Angle of printed labels in radians (double))
        $(LI "alpha": Alpha value of the drawn object (double))
        $(LI "mask": Mask the area outside the axes. Prevents you from drawing outside of the area (bool))
        $(LI "fill": Whether to fill the object/holds the alpha value to fill with (double).))
    +/
template Aes(Specs...)
{
    import std.traits : Identity;
    import std.typecons : isTuple;
    import std.typetuple : staticMap, TypeTuple;
    import std.range : isInputRange;

    // Parse (type,name) pairs (FieldSpecs) out of the specified
    // arguments. Some fields would have name, others not.
    template parseSpecs(Specs...)
    {
        static if (Specs.length == 0)
        {
            alias parseSpecs = TypeTuple!();
        }
        else static if (is(Specs[0]) && isInputRange!(Specs[0]))
        {
            static if (is(typeof(Specs[1]) : string))
            {
                alias parseSpecs = TypeTuple!(FieldSpec!(Specs[0 .. 2]), parseSpecs!(Specs[2 .. $]));
            }
            else
            {
                alias parseSpecs = TypeTuple!(FieldSpec!(Specs[0]), parseSpecs!(Specs[1 .. $]));
            }
        }
        else
        {
            static assert(0,
                "Attempted to instantiate Tuple with an " ~ "invalid argument: " ~ Specs[0].stringof);
        }
    }

    template FieldSpec(T, string s = "")
    {
        alias Type = T;
        alias name = s;
    }

    alias fieldSpecs = parseSpecs!Specs;

    // Used with staticMap.
    alias extractType(alias spec) = spec.Type;
    alias extractName(alias spec) = spec.name;

    // Generates named fields as follows:
    //    alias name_0 = Identity!(field[0]);
    //    alias name_1 = Identity!(field[1]);
    //      :
    // NOTE: field[k] is an expression (which yields a symbol of a
    //       variable) and can't be aliased directly.
    string injectNamedFields()
    {
        string decl = "";

        foreach (i, name; staticMap!(extractName, fieldSpecs))
        {
            import std.format : format;

            decl ~= format("alias _%s = Identity!(field[%s]);", i, i);
            if (name.length != 0)
            {
                decl ~= format("alias %s = _%s;", name, i);
            }
        }
        return decl;
    }

    alias fieldNames = staticMap!(extractName, fieldSpecs);

    string injectFront()
    {
        import std.format : format;

        string decl = "auto front() { import std.range : ElementType;";
        decl ~= "import std.typecons : Tuple; import std.range : front;";

        string tupleType = "Tuple!(";
        string values = "(";

        foreach (i, name; fieldNames)
        {

            tupleType ~= format(q{typeof(%s.front),}, name);
            tupleType ~= "q{" ~ name ~ "},";
            values ~= format("this.%s.front,", name);
        }

        decl ~= "return " ~ tupleType[0 .. $ - 1] ~ ")" ~ values[0 .. $ - 1] ~ "); }";
        //string decl2 = format("auto front() { import std.stdio; \"%s\".writeln; return 0.0; }", decl);
        return decl;
    }

    // Returns Specs for a subtuple this[from .. to] preserving field
    // names if any.
    alias sliceSpecs(size_t from, size_t to) = staticMap!(expandSpec, fieldSpecs[from .. to]);

    template expandSpec(alias spec)
    {
        static if (spec.name.length == 0)
        {
            alias expandSpec = TypeTuple!(spec.Type);
        }
        else
        {
            alias expandSpec = TypeTuple!(spec.Type, spec.name);
        }
    }

    enum areCompatibleTuples(Tup1, Tup2, string op) = isTuple!Tup2 && is(typeof({
        Tup1 tup1 = void;
        Tup2 tup2 = void;
        static assert(tup1.field.length == tup2.field.length);
        foreach (i, _;
        Tup1.Types)
        {
            auto lhs = typeof(tup1.field[i]).init;
            auto rhs = typeof(tup2.field[i]).init;
            static if (op == "=")
                lhs = rhs;
            else
                auto result = mixin("lhs " ~ op ~ " rhs");
        }
    }));

    enum areBuildCompatibleTuples(Tup1, Tup2) = isTuple!Tup2 && is(typeof({
        static assert(Tup1.Types.length == Tup2.Types.length);
        foreach (i, _;
        Tup1.Types)
        static assert(isBuildable!(Tup1.Types[i], Tup2.Types[i]));
    }));

    /+ Returns $(D true) iff a $(D T) can be initialized from a $(D U). +/
    enum isBuildable(T, U) = is(typeof({ U u = U.init; T t = u; }));
    /+ Helper for partial instanciation +/
    template isBuildableFrom(U)
    {
        enum isBuildableFrom(T) = isBuildable!(T, U);
    }
    struct Aes
    {
        /**
         * The type of the tuple's components.
         */
        alias Types = staticMap!(extractType, fieldSpecs);

        /**
         * The names of the tuple's components. Unnamed fields have empty names.
         *
         * Examples:
         * ----
         * alias Fields = Tuple!(int, "id", string, float);
         * static assert(Fields.fieldNames == TypeTuple!("id", "", ""));
         * ----
         */
        alias fieldNames = staticMap!(extractName, fieldSpecs);

        /**
         * Use $(D t.expand) for a tuple $(D t) to expand it into its
         * components. The result of $(D expand) acts as if the tuple components
         * were listed as a list of values. (Ordinarily, a $(D Tuple) acts as a
         * single value.)
         *
         * Examples:
         * ----
         * auto t = tuple(1, " hello ", 2.3);
         * writeln(t);        // Tuple!(int, string, double)(1, " hello ", 2.3)
         * writeln(t.expand); // 1 hello 2.3
         * ----
         */
        Types expand;
        mixin(injectNamedFields());

        // backwards compatibility
        alias field = expand;

        /**
         * Constructor taking one value for each field.
         */
        static if (Types.length > 0)
        {
            this(Types values)
            {
                field[] = values[];
            }
        }

        /**
         * Constructor taking a compatible array.
         *
         * Examples:
         * ----
         * int[2] ints;
         * Tuple!(int, int) t = ints;
         * ----
         */
        /+this(U, size_t n)(U[n] values) if (n == Types.length
                && allSatisfy!(isBuildableFrom!U, Types))
        {
            foreach (i, _; Types)
            {
                field[i] = values[i];
            }
        }+/

        /**
         * Constructor taking a compatible tuple.
         */
        this(U)(U another) if (areBuildCompatibleTuples!(typeof(this), U))
        {
            field[] = another.field[];
        }

        mixin(injectFront());

        ///
        void popFront()
        {
            import std.range : popFront;

            foreach (i, _; Types[0 .. $])
            {
                field[i].popFront();
            }
        }

        ///
        auto save() const
        {
            return this;
        }

        ///
        @property bool empty()
        {
            if (length == 0)
                return true;
            return false;
        }

        ///
        size_t length()
        {
            import std.algorithm : min;
            import std.range : walkLength, isInfinite;

            size_t l = size_t.max;
            foreach (i, type; Types[0 .. $])
            {
                static if (!isInfinite!type)
                {
                    if (field[i].walkLength < l)
                        l = field[i].walkLength;
                }
            }
            return l;
        }

        /**
         * Comparison for equality.
         */
        bool opEquals(R)(R rhs) if (areCompatibleTuples!(typeof(this), R, "=="))
        {
            return field[] == rhs.field[];
        }

        /// ditto
        bool opEquals(R)(R rhs) const if (areCompatibleTuples!(typeof(this), R, "=="))
        {
            return field[] == rhs.field[];
        }

        /**
         * Comparison for ordering.
         */
        int opCmp(R)(R rhs) if (areCompatibleTuples!(typeof(this), R, "<"))
        {
            foreach (i, Unused; Types)
            {
                if (field[i] != rhs.field[i])
                {
                    return field[i] < rhs.field[i] ? -1 : 1;
                }
            }
            return 0;
        }

        /// ditto
        int opCmp(R)(R rhs) const if (areCompatibleTuples!(typeof(this), R, "<"))
        {
            foreach (i, Unused; Types)
            {
                if (field[i] != rhs.field[i])
                {
                    return field[i] < rhs.field[i] ? -1 : 1;
                }
            }
            return 0;
        }

        /**
         * Assignment from another tuple. Each element of the source must be
         * implicitly assignable to the respective element of the target.
         */
        void opAssign(R)(auto ref R rhs) if (areCompatibleTuples!(typeof(this), R,
                "="))
        {
            import std.algorithm : swap;

            static if (is(R : Tuple!Types) && !__traits(isRef, rhs))
            {
                if (__ctfe)
                {
                    // Cannot use swap at compile time
                    field[] = rhs.field[];
                }
                else
                {
                    // Use swap-and-destroy to optimize rvalue assignment
                    swap!(Tuple!Types)(this, rhs);
                }
            }
            else
            {
                // Do not swap; opAssign should be called on the fields.
                field[] = rhs.field[];
            }
        }

        /**
         * Takes a slice of the tuple.
         *
         * Examples:
         * ----
         * Tuple!(int, string, float, double) a;
         * a[1] = "abc";
         * a[2] = 4.5;
         * auto s = a.slice!(1, 3);
         * static assert(is(typeof(s) == Tuple!(string, float)));
         * assert(s[0] == "abc" && s[1] == 4.5);
         * ----
         */
        @property ref Tuple!(sliceSpecs!(from, to)) slice(size_t from, size_t to)() @trusted if (
                from <= to && to <= Types.length)
        {
            return *cast(typeof(return)*)&(field[from]);
        }

        ///
        size_t toHash() const nothrow @trusted
        {
            size_t h = 0;
            foreach (i, T; Types)
                h += typeid(T).getHash(cast(const void*)&field[i]);
            return h;
        }

        /**
         * Converts to string.
         */
        void toString(DG)(scope DG sink)
        {
            enum header = typeof(this).stringof ~ "(", footer = ")", separator = ", ";
            sink(header);
            foreach (i, Type; Types)
            {
                static if (i > 0)
                {
                    sink(separator);
                }
                // TODO: Change this once toString() works for shared objects.
                static if (is(Type == class) && is(typeof(Type.init) == shared))
                {
                    sink(Type.stringof);
                }
                else
                {
                    import std.format : FormatSpec, formatElement;

                    FormatSpec!char f;
                    formatElement(sink, field[i], f);
                }
            }
            sink(footer);
        }

        ///
        string toString()()
        {
            import std.conv : to;

            return this.to!string;
        }
    }
}

unittest
{
    auto tup = Aes!(double[], "x", double[], "y", string[], "colour")([0, 1],
        [2, 1], ["white", "white2"]);
    auto tup2 = Aes!(double[], "x", double[], "y")([0, 1], [2, 1]);
    assertEqual(tup.colour, ["white", "white2"]);
    assertEqual(tup.length, 2);
    assertEqual(tup2.length, 2);

    tup2.x ~= 0.0;
    tup2.x ~= 0.0;
    assertEqual(tup2.length, 2);
    tup2.y ~= 0.0;
    assertEqual(tup2.length, 3);
}

/// Basic Aes usage
unittest
{
    auto aes = Aes!(double[], "x", double[], "y", string[], "colour")([0, 1],
        [2, 1], ["white", "white2"]);

    aes.popFront;
    assertEqual(aes.front.y, 1);
    assertEqual(aes.front.colour, "white2");

    auto aes2 = Aes!(double[], "x", double[], "y")([0, 1], [2, 1]);
    assertEqual(aes2.front.y, 2);

    import std.range : repeat;

    auto xs = repeat(0);
    auto aes3 = Aes!(typeof(xs), "x", double[], "y")(xs, [2, 1]);

    assertEqual(aes3.front.x, 0);
    aes3.popFront;
    aes3.popFront;
    assertEqual(aes3.empty, true);

}

/++
    Groups data by colour label etc.

    Will also add DefaultValues for label etc to the data. It is also possible to specify exactly what to group by on as a template parameter. See example.
+/
template group(Specs...)
{
    string buildExtractKey()
    {
        static if (Specs.length == 0)
        {
            import std.typetuple : TypeTuple;
            alias Specs = TypeTuple!("alpha","colour","label");
        }
        string types = "";
        string values = "";
        foreach( spec; Specs )
        {
            types ~= "typeof(a." ~ spec ~"),";
            values ~= "a." ~ spec ~",";
        }
        string str = "auto extractKey(T)(T a) 
            { return Tuple!(" ~ types[0..$-1] ~ ")(" ~ values[0..$-1] ~ "); }";
        return str;
    }
    
    auto group(AES)(AES aes)
    {
        import std.stdio;
        mixin(buildExtractKey());

        // Attach all default fields
        auto merged = DefaultValues.mergeRange( aes );
        extractKey( merged.front );

        typeof(merged.front())[][typeof(extractKey(merged.front))] grouped;

        // Extract keys for aa and store in aa. Return the values of the aa
        foreach( tup; merged )
        {
            auto key = extractKey(tup);
            if (key in grouped)
                grouped[key] ~= tup;
            else
                grouped[key] = [tup];
        }
        return grouped.values;
    }
}

///
unittest
{
    import std.range : walkLength;
    auto aes = Aes!(double[], "x", string[], "colour", double[], "alpha")
        ([0,1,2,3], ["a","a","b","b"], [0,1,0,1]);

    assertEqual(group!("colour","alpha")(aes).walkLength,4);
    assertEqual(group!("alpha")(aes).walkLength,2);

    assertEqual(group(aes).walkLength,4);
}

///
unittest
{
    auto aes = Aes!(double[], "x", double[], "y", string[], "colour")([1.0,
        2.0, 1.1], [3.0, 1.5, 1.1], ["a", "b", "a"]);

    import std.range : walkLength, front, popFront;

    auto grouped = aes.group;
    assertEqual(grouped.walkLength, 2);
    assertEqual(grouped.front.walkLength, 2);
    grouped.popFront;
    assertEqual(grouped.front.walkLength, 1);
}

///
import std.range : isInputRange;

alias DataID = Tuple!(double, string);

///
struct NumericLabel(T) if (isInputRange!T)
{
    import std.range : ElementType;
    import std.traits : isNumeric;

    alias E = ElementType!T;

    ///
    this(T range)
    {
        original = range;
    }

    ///
    @property auto front()
    {
        import std.typecons : Tuple;
        import std.range : front;
        import std.conv : to;

        static if (isNumeric!E)
            return DataID(original.front.to!double, original.front.to!string);
        else
        {
            if (original.front !in fromLabelMap)
            {
                fromLabelMap[original.front] = fromLabelMap.length.to!double;
                //toLabelMap[fromLabelMap[original.front]] 
                //    = original.front;
            }
            return DataID(fromLabelMap[original.front], original.front.to!string,
                );
        }
    }

    ///
    void popFront()
    {
        import std.range : popFront;

        original.popFront;
    }

    ///
    @property bool empty()
    {
        import std.range : empty;

        return original.empty;
    }

    ///
    @property bool numeric()
    {
        static if (isNumeric!E)
            return true;
        else
            return false;
    }

private:
    T original;
    //E[double] toLabelMap;
    double[E] fromLabelMap;
}

unittest
{
    import std.stdio : writeln;
    import std.array : array;
    import std.algorithm : map;

    auto num = NumericLabel!(double[])([0.0, 0.1, 1.0, 0.0]);
    assertEqual(num.map!((a) => a[0]).array, [0.0, 0.1, 1.0, 0.0]);
    assertEqual(num.map!((a) => a[1]).array, ["0", "0.1", "1", "0"]);
    auto strs = NumericLabel!(string[])(["a", "c", "b", "a"]);
    assertEqual(strs.map!((a) => a[0]).array, [0, 1, 2.0, 0.0]);
    assertEqual(strs.map!((a) => a[1]).array, ["a", "c", "b", "a"]);
}

unittest
{
    import painlesstraits;

    auto t = Tuple!(double,"x")(1.0);

    static assert(isFieldOrProperty!(t.x));
}

/++
Merge two types by their members. 

If it has similar named members, then it uses the second one.

returns a named Tuple (or Aes) with all the members and their values. 
+/
template merge(T, U)
{
    import std.traits;
    import painlesstraits;
    auto generateCode()
    {
        import std.string : split;
        string typing = "Tuple!(";
        //string typing = T.stringof.split("!")[0] ~ "!(";
        //string typingU = U.stringof.split("!")[0] ~ "!(";
        string variables = "(";
        foreach (name; __traits(allMembers, U))
        {
            static if (__traits(compiles, isFieldOrProperty!(
                            __traits(getMember, U, name)))
                    && __traits(compiles, ( in U u ) {
                        auto a = __traits(getMember, u, name);
                        Tuple!(typeof(a),name)(a); } )
                    && isFieldOrProperty!(__traits(getMember,U,name))
                    && name[0] != "_"[0] )
            {
                typing ~= "typeof(other." ~ name ~ "),\"" ~ name ~ "\",";
                variables ~= "other." ~ name ~ ",";
            }
        }

        foreach (name; __traits(allMembers, T))
        {
            static if (__traits(compiles, isFieldOrProperty!(
                __traits(getMember, T, name)))
                     && __traits(compiles, ( in T u ) {
                auto a = __traits(getMember, u, name); 
                Tuple!(typeof(a),name)(a); } )
                && isFieldOrProperty!(__traits(getMember,T,name))
                     && name[0] != "_"[0] )
                {
                bool contains = false;
                foreach (name2; __traits(allMembers, U))
                {
                    if (name == name2)
                        contains = true;
                }
                if (!contains)
                {
                    typing ~= "typeof(base." ~ name ~ "),\"" ~ name ~ "\",";
                    variables ~= "base." ~ name ~ ",";
                }
            }
        }
        return "return " ~ typing[0 .. $ - 1] ~ ")" ~ variables[0 .. $ - 1] ~ ");";
    }

    auto merge(T base, U other)
    {
        mixin(generateCode());
    }
}

///
unittest
{
    import std.range : front;

    auto xs = ["a", "b"];
    auto ys = ["c", "d"];
    auto labels = ["e", "f"];
    auto aes = Aes!(string[], "x", string[], "y", string[], "label")(xs, ys, labels);

    auto nlAes = merge(aes, Aes!(NumericLabel!(string[]), "x",
        NumericLabel!(string[]), "y")(NumericLabel!(string[])(aes.x),
        NumericLabel!(string[])(aes.y)));

    assertEqual(nlAes.x.front[0], 0);
    assertEqual(nlAes.label.front, "e");
}

unittest
{
    auto pnt = Tuple!(double, "x", double, "y", string, "label" )( 1.0, 2.0, "Point" );
    auto merged = DefaultValues.merge( pnt );
    assertEqual( merged.x, 1.0 );
    assertEqual( merged.y, 2.0 );
    assertEqual( merged.colour, "black" );
    assertEqual( merged.label, "Point" );
}

unittest
{
    import std.range : walkLength;
    auto m = [DefaultValues].mergeRange( Aes!(double[], "x")([1.0]));
    assertEqual( m.walkLength, 1);
}

/// 
unittest
{
    struct Point { double x; double y; string label = "Point"; }
    auto pnt = Point( 1.0, 2.0 );

    auto merged = DefaultValues.merge( pnt );
    assertEqual( merged.x, 1.0 );
    assertEqual( merged.y, 2.0 );
    assertEqual( merged.colour, "black" );
    assertEqual( merged.label, "Point" );
}

/++
  Merge the elements of two ranges. If first is not a range then merge that with each element of the second range.
+/
auto mergeRange( R1, R2 )( R1 r1, R2 r2 )
{
    import std.array : array;
    import std.range : zip, walkLength, repeat;
    import std.algorithm : map;
    static if (isInputRange!R1 && isInputRange!R2)
        return r1.zip(r2).array.map!((a) => a[0].merge( a[1] ) );
    else
        return zip( r1.repeat(r2.walkLength),
            r2).array.map!((a) => a[0].merge( a[1] ) );
}

///
unittest
{
    import std.range : front;

    auto xs = ["a", "b"];
    auto ys = ["c", "d"];
    auto labels = ["e", "f"];
    auto aes = Aes!(string[], "x", string[], "y", string[], "label")(xs, ys, labels);
    auto nlAes = mergeRange(DefaultValues, aes );
    assertEqual(nlAes.front.x, "a");
    assertEqual(nlAes.front.label, "e");
    assertEqual(nlAes.front.colour, "black");
}

///
unittest
{
    import std.range : front;

    auto xs = ["a", "b"];
    auto ys = ["c", "d"];
    auto labels = ["e", "f"];
    auto aes = Aes!(string[], "x", string[], "y", string[], "label")(xs, ys, labels);

    auto nlAes = mergeRange(aes, Aes!(NumericLabel!(string[]), "x",
        NumericLabel!(string[]), "y")(NumericLabel!(string[])(aes.x),
        NumericLabel!(string[])(aes.y)));

    assertEqual(nlAes.front.x[0], 0);
    assertEqual(nlAes.front.label, "e");
}